A northern New York couple used "coercion tactics" to lure two Amish sisters into their car during a kidnapping, the St. Lawrence County sheriff said today, a day after the couple was arrested.

Police arrested Stephen Howells II, 39, and Nicole Vaisey, 25, both of Hermon, late Friday. They were each charged with two counts of first-degree kidnapping, indicating that they intended to physically harm or sexually abuse the girls.

St. Lawrence County Sheriff Kevin Wells said the couple and the children didn't know each other but that the kidnapping was planned.

"The motive was to victimize children," Wells said during a news conference. "The girls have been victims of crimes. That's the only detail we'll give."

Howells and Vaisey will face other charges, including possible federal charges, Wells said, adding that they may have planned to kidnap more girls. Both suspects are being held without bail.

District Attorney Mary Rain said information provided by the girls helped lead to Howells and Vaisey. The suspects' home is about 13 miles from where the girls live.

A preliminary hearing was scheduled for Thursday afternoon.

Jason Hunter/The Watertown Daily Times/AP Photo

Supporters gather on the porch of a house at the intersection of Route 812 and Mt. Alone Road

The 12- and 7-year-old sisters were abducted Wednesday night in Oswegatchie, N.Y., a rural town located near the Canadian border, when they went out to sell vegetables to a car at the stand, according to police.

The next night, they showed up on the doorstep of Jeff and Pam Stinson barefoot, cold, wet and hungry, the couple told ABC News.

The Stinsons opened their door to the two girls, who asked the couple to drive them back home. The Stinsons said they recognized the girls because they had bought produce from them before and were aware of news reports about their abduction.

When the girls arrived on their doorstep, the Stinsons fed them watermelon and grape juice and the girls were so hungry they couldn't stop eating the watermelon.

"They ate that watermelon in 30 seconds. It was fast," said Jeff Stinson.

Jeff Stinson knew exactly where the two girls lived because he had bought corn from the elder girl before at their vegetable stand.

An Amber Alert had been issued Wednesday night after a witness reported seeing a vehicle pull up to the stand, the girls go out to wait on them and then the driver of the car put something in the backseat. When the car drove away, the witness told police the children were gone.

Rain said the sisters were still wearing Amish attire when they were found.